I got the brown out once by putting 4 gallons of white vinegar and cold water (enough water to just cover quilt) in my washing machine. I let it soak. Agitating only with my hands. When it appeared to be all out, I rinsed it in cold water two times agitating only with my hands but spinning it out. It neutralized the brown marks -they came out. I googled "how to get brown marks out of quilt" and it gave me directions for the white vinegar and water. It saved mine,